Device for vertically positioning the props of a mine roof supporting frame

ABSTRACT

A device for vertically positioning the props of a mine roof supporting frame in which a cap is supported by a plurality of props against a floor frame, comprising two claws being disposed so as to be movable towards each other; a stationary abutment, the two claws being arranged both sides of the abutments; a post being disposed stationarily on the floor frame, the abutment being located on the post; a hydraulic cylinder-and-piston arrangement being adapted for locating a prop between the two claws, the piston of the hydraulic cylinder-and-piston arrangement being disposed between the two claws; and pressurerelief valve means for maintaining constant the positioning force and thereby limiting the positioning force so that when excessive forces occur due to ground movements the pressure relief valve means opens before the props are damaged, the valve means being disposed in the working chamber of the hydraulic cylinder-andpiston arrangement.

United States Patent [191 Sigott et al.

[ 1 Sept. 3, 1974 DEVICE FOR VERTICALLY POSITIONING THE PROPS OF A MINEROOF SUPPORTING FRAME [75] Inventors: Siegfried Sigott, Alfred Zitz;

Heinrich Sussenbeck, all of Zeltweg, Austria [73] Assignee:Oesterreichisch-Alpine Montangesellschaft, Vienna, Austria [22] Filed;Dec. 14, 1972 [21] Appl. No.: 315,238

[30] Foreign Application Priority Data Dec. 14, 1971 Austria 10739/71[52] US. Cl. 61/45 D, 248/357 [51] Int. Cl E21d 15/44 [58] Field ofSearch 61/45 D; 248/357; 91/189; 299/31, 33

[56] References Cited UNITED STATES PATENTS 3,016,992 l/1962 Wilson92/52 X 3,309,054 3/1967 Davis-Ratcliffe 248/357 X FOREIGN PATENTS ORAPPLICATIONS 779,791 7/1957 Great Britain 248/357 Primary ExaminerDennisL. Taylor Attorney, Agent, or Firml-lolman & Stern [57] ABSTRACT Adevice for vertically positioning the props of a mine roof supportingframe in which a cap is supported by a plurality of props against afloor frame, comprising two claws being disposed so as to be movabletowards each other; a stationary abutment, the two claws being arrangedboth sides of the abutments; a post being disposed stationarily on thefloor frame, the abutment being located on the post; a hydrauliccylinder-andpiston arrangement being adapted for locating a prop betweenthe two claws, the piston of the hydraulic cylinder-and-pistonarrangement being disposed between the two claws; and pressure-reliefvalve means for maintaining constant the positioning force and therebylimiting the positioning force so that when excessive forces occur dueto ground movements the pressure relief valve means opens before theprops are damaged, the valve means being disposed in the working chamberof the hydraulic cylinder-and-piston arrangement.

10 Claims, 4 Drawing Figures PATENTEDSEP3 m4 sum 1. u; 2

FIG.

. PROPS OF A MINE ROOF SUPPORTING FRAME BACKGROUND OF THE INVENTION Thepresent invention refers to a device for vertically positioning theprops of a mine roof supporting frame in which the cap is supported by aplurality of props against a floor frame. Such known devices forvertically positioning the props are formed of resilient elements. Suchresilient elements are suitable to avoid folding up of the mine roofsupporting frame and to maintain the props in upright direction as longas these props are not subjected to laterally acting forces, suchresilient elements are, however, unsuitable for exerting sufficientlystrong positioning forces. Such elastic members are not suitable formaintaining the props in vertical direction relative to the mine floorwhen the props are subjected to laterally acting forces.

SUMMARY OF THE INVENTION The invention now aims at avoiding thesedrawbacks and is essentially characterized in that two claws arearranged at both sides of an abutment stationarily arranged relative tothe floor frame, in that these claws are arranged for being pressedtogether by a hydraulic cylinder and in that the prop is located betweenthese claws, noting that to the working chamber of the hydrauliccylinder a pressure relief valve is connected for limiting thepositioning force. In this manner the prop can be subjected to aconsiderable positioning force which may surpass even laterally actingforces. In view of the fact that the seam to be exploited is not alwaysin a horizontal position, the position of props arranged vertically tothe mine floor can substantially deviate from the perpendicularposition, and it is just in this case that considerable laterally actingforces may occur, which, however, may be overcome by a positioningdevice according to the invention. When using a hydraulic pressurerelief valve, the positioning force can be kept constant and by thuslimiting the positioning force any risk of breakage can also be avoided.By providing between the claws a stationary abutment, the normalposition of the prop relative to the mine floor is determined bylimiting the positioning movement. Props assuming an oblique positionare thus drawn in direction to the stationary abutment and therewithinto normal position. Only when both claws are engaging the stationaryabutment, the prop assumes a normal position in which the claws surroundthe prop without play or with little play. The positioning force exertedon one prop is effective also on the other props because these props arecoupled together by means of the floor frame and the cap. In a usualarrangement, in which two props are arranged side by side and two suchpairs of props are arranged, seen in direction of the cap, one after theother, the positioning means is conveniently arranged for acting on theprops located side by side.

According to a preferred embodiment of the invention, the claws areacting on the prop and, respectively, the props at a level correspondingto at least one third of the length of the prop or props. In thismanner, the lever arm on which the positioning force is acting isrelatively long so that relatively considerable positioning forces canbe exerted. According to an advantageous embodiment, the claws and,conveniently, also the abutment are arranged on a post surrounding theprop.

In a usual construction, according to which two props are arranged sideby side, the claws are, conveniently, dual-acting and arranged forsurroundingly grasping with both of their arms the props arranged sideby side, noting that the hydraulic cylinder is acting upon the claws ata location between the props and that the abutment is arranged betweenboth props.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is further illustratedwith reference to the drawing in which a device according to theinvention is schematically shown.

FIG. 1 shows a side elevation of a mine roof supporting frame equippedwith a positioning device for vertically arranging the props relative tothe mine floor. FIG. 2 shows in a greater scale the positioning devicein a perspective view. FIGS. 3 and 4 show the arrangement of the claws,noting that FIG. 3 represents a top plan view and FIG. 4 represents asection along line IV-IV of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Cap 1 of the mine roofsupporting frame is supported against the floor frame 6 by means of fourprops 2, 3 and 4, 5. The props 2, 3, 4 and 5 are pivotally connected tofloor frame 6 and cap 1.

Two double-arm claws 8 and 9 are slidingly guided within guides 10 and11 arranged on a post 7. The claws 8 and 9 are grasping the props 2 and3 in surrounding relation at the area of their rounded recesses 12. Anabutment I3 is stationarily arranged on the post 7. The abutment 13 hasan opening 14 through which two tongues 15 and 16 are inserted. Claw 8is welded to the tongues 15 and 16 and a hydraulic cylinder 17 isconnected to these tongues 15 and 16 and the claw 8. The piston 18 ofthe hydraulic cylinder 17 has a piston rod 19 which is connected bymeans of a bolt 20 to claw 9. According to the embodiment shown in FIG.4 a portion of the tongues 15 and 16 is forming the body of thehydraulic cylinder 17 and to this body and the tongues 15 and 16 arewelded with their portions 15, 15'. Bolt 20 is introduced into elongatedslots 21 of tongues 15 and 16.

When introducing hydraulic fluid into the working chamber 22 of cylinder17, claw 9 is drawn by piston rod 19 and bolt 20 in direction to claw 8,both parts (arms) of which are welded to cylinder 17. As soon as one ofthe claws is engaging with its engaging surface 23 the stationaryabutment 13, the other one of the claws, i.e., claw 8 or claw 9, isdrawing both props 2 and 3 in direction to abutment 13 and thus intononnal position in which finally also the engaging surface 23 of theother claw is engaging the stationary abutment 13. In this position,props 2 and 3 assume a vertical position, and, in view of props 4 and 5being coupled to cap 1 and floor frame 6, also props 4 and 5 werebrought in vertical position. In this position the rounded recesses 12of claws 8 and 9 are engaging props 2 and 3 without any play or withlittle play.

A pressure relief valve 24 is connected to working chamber 22 forlimiting the positioning force and, respectively, maintaining constantthe full positioning force attained. If the props are pressed in obliqueposition by eventually occuring ground movements, the claws may yielduntil the constant positioning force is no more exceeded.

Post 7 is, as shown in the drawing, of such a height that the claws 8and 9, which are arranged on top of the post, engage the props at alevel corresponding to at least one third of their length.

The lower tongue 16 is laterally guided between guiding ledges. Tonguesand 16 are secured against movement in vertical direction by the opening14 provided within abutment 13. In total, the claws are, thereforesecured against movement in all lateral directions as well as invertical direction.

We claim:

1. A device for vertically positioning the props of a mine roofsupporting frame in which a cap is supported by a plurality of propsagainst a floor frame, said device comprising:

two claws being disposed so as to be movable towards each other;

a stationary abutment, said two claws being arranged on both sides ofsaid abutment;

a post being disposed stationarily on the floor frame,

said abutment being located on said post;

a hydraulic cylinder-and-piston arrangement being adapted for locating aprop between said two claws, the piston of said hydrauliccylinder-andpiston arrangement being disposed between said two claws;and

pressure relief valve means for maintaining constant the positioningforce and thereby limiting the positioning force so that when excessforces occur due to ground movement said pressure relief valve meansopens before the props are damaged, said valve means being disposed inthe working chamber of said hydraulic cylinder-and-piston arrangement.

2. A device as claimed in claim 1, wherein said two claws are engagingthe prop at a level corresponding to at least one third of the length ofthe prop.

3. A device as claimed in claim 2, wherein said two claws are engagingsaid stationary abutment when assuming the position in which theysurround the prop without play or with little play.

4. A device as claimed in claim 2, wherein said two claws and,conveniently, also said abutment are arranged on said post surroundingthe prop.

5. A device as claimed in claim 2, wherein said claws are twin-arm clawsand surroundingly engage the prop arranged side by side, said hydrauliccylinder-andpiston arrangement acting on said two claws between the propand wherein said abutment is arranged between the prop.

6. A device as claimed in claim 2, further including said hydrauliccylinder-and-piston arrangement and two tongues, which are disposedadjacent to opposite sides of said two claws being rigidly connected toone of said two claws and the other one of said two claws being guidedby means of said two tongues and connected with a piston rod of saidhydraulic cylinder-andpiston arrangement.

7. A device as claimed in claim 6, wherein said stationary abutment hasan opening through which said tongues are inserted.

8. A device as claimed in claim 2, wherein said post is provided withguides laterally engaging and guiding the lower one of said two tongues,said two claws being adapted for sliding movement on said guides.

9. A device as claimed in claim 2, wherein said two claws have anarcuate engaging surface for engaging the prop also laterally.

10. A device as claimed in claim 2, wherein said two claws are arrangedat the pair of props being most remotely located from the cutting face.

1. A device for vertically positioning the props of a mine roofsupporting frame in which a cap is supported by a plurality of propsagainst a floor frame, said device comprising: two claws being disposedso as to be movable towards each other; a stationary abutment, said twoclaws being arranged on both sides of said abutment; a post beingdisposed stationarily on the floor frame, said abutment being located onsaid post; a hydraulic cylinder-and-piston arrangement being adapted forlocating a prop between said two claws, the piston of said hydrauliccylinder-and-piston arrangement being disposed between said two claws;and pressure relief valve means for maintaining constant the positioningforce and thereby limiting the positioning force so that when excessforces occur due to ground movement said pressure relief valve meansopens before the props are damaged, said valve means being disposed inthe working chamber of said hydraulic cylinder-and-piston arrangement.2. A device as claimed in claim 1, wherein said two claws are engagingthe prop at a level corresponding to at least one third of the length ofthe prop.
 3. A device as claimed in claim 2, wherein said two claws areengaging said stationary abutment when assuming the position in whichthey surround the prop without play or with little play.
 4. A device asclaimed in claim 2, wherein said two claws and, conveniently, also saidabutment are arranged on said post surrounding the prop.
 5. A device asclaimed in claim 2, wherein said claws are twin-arm claws andsurroundingly engage the prop arranged side by side, said hydrauliccylinder-and-piston arrangement acting on said two claws between theprop and wherein said abutment is arranged between the prop.
 6. A deviceas claimed in claim 2, further including said hydrauliccylinder-and-piston arrangement and two tongues, which are disposedadjacent to opposite sides of said two claws being rigidly connected toone of said two claws and the other one of said two claws being guidedby means of said two tongues and connected with a piston rod of saidhydraulic cylinder-and-piston arrangement.
 7. A device as claimed inclaim 6, wherein said stationary abutment has an opening through whichsaid tongues are inserted.
 8. A device as claimed in claim 2, whereinsaid post is provided with guides laterally engaging and guiding thelower one of said two tongues, said two claws being adapted for slidingmovement on said guides.
 9. A device as claimed in claim 2, wherein saidtwo claws have an arcuate engaging surface for engaging the prop alsolaterally.
 10. A device as claimed in claim 2, wherein said two clawsare arranged at the pair of props being most remotely located from thecutting face.